Application of multivariable control using artificial neural networks in a debutanizer distillation column

LOPES, Jose Soares Batista et al. Application of multivariable control using artificial neural networks in a debutanizer distillation column.In: INTERNATIONAL CONGRESS OF MECHANICAL ENGINEERING - COBEM, 19, 5-9 nov. 2007, Brasilia. Anais... Brasilia, 2007Abstract. This work has as objective to develop a control strategy based on neural identification of a mutivariable input- mutivariable output (MIMO) process. The plant to control was simulated in software HYSYS as a classic debutanizer column. Debutanizer distillation column is used to remove the litht components from the gasoline stream to produce Liquefied Petroleum Gas (LPG). The quality control of the product taking away from the top of the tower is affected by the Outflow Control (FIC-100) and the Temperature Control (TIC-100).The process variables chosen are concentration of i-pentene existing in butanes stream and concentration of i-butene existing in C5+ stream. The manipulated variables chosen are reflux flow rate (the setpoint of FIC-100 in h/m3) and thermal load (the setpoint of TIC-100 in oC). The FIC- 100 is responsible for the control of reflux and the TIC-100 for the control of the temperature in the debutanizer column, changing its thermal load to keeping the C5+ production at acceptable level. The purpose is to substitute two physical controllers, FIC-100 and TIC-100, by a neural control system. An important feature of this work is the use of a control strategy composed by two neural network structures: Neuroidentifier and Neurocontroller, responsible respectively for identifying and controlling the process.The software implementation of the artificial neural networks is made using Borland C++ Builder, and its communication with HYSYS is carried through the Microsoft Component Object Model (COM

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Silos circulares em alvenaria de blocos cerâmicos : análise da influência da forma no comportamento estrutural

O crescimento da produção brasileira de grãos nos últimos anos aumenta a importância de uma maior capacidade de armazenamento destes na cadeia produtiva do Brasil. Visto que a malha de transporte rodoviário e ferroviário não apresenta as melhores condições para o escoamento da produção, o aumento do armazenamento local surge como opção para se amenizar estas limitações. Atualmente, a solução tem sido a construção de silos metálicos, porém a necessidade de mão de obra especializada e os altos custos envolvidos muitas vezes tornam inviável a execução destes em pequenas e médias propriedades. Neste contexto, silos em alvenaria de blocos cerâmicos apresentam-se como alternativa, principalmente pela possibilidade de utilização de mão de obra e materiais locais, possibilitando a difusão deste sistema em todo o País. A utilização de blocos cerâmicos proporcionará, pelo maior peso próprio da estrutura, um melhor comportamento estrutural frente às ações do vento, além de melhor comportamento térmico no armazenamento dos grãos e menor consumo energético em comparação com o aço e o concreto. Como não se encontra um procedimento racional de dimensionamento deste tipo de estruturas, este trabalho analisou como a variação da relação de forma (h/dc) influencia no comportamento estrutural de silos em alvenaria de blocos cerâmicos

Screening for symptoms of anxiety and depression in patients admitted to a university hospital with acute coronary syndrome

Abstract Objective: To investigate the prevalence of anxiety and depression in patients admitted for acute coronary syndrome to a university hospital and to examine associations with use of psychotropic drugs. Methods: Ninety-one patients who had had an acute coronary event were enrolled on this cross-sectional prevalence study. Characteristics of the study population and the prevalence rates of depression and anxiety in the sample were assessed using the Hospital São Lucas da Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS) psychiatric consultation protocol, which includes clinical and sociodemographic data, and the Hospital Anxiety and Depression Scale (HADS). Results: The prevalence of symptoms of anxiety was 48.4% (44 patients) and the prevalence of depressive symptoms was 26.4% (24 patients). Of these, 19 patients (20.9% of the whole sample) had scores indicative of both types of symptoms concomitantly. Considering the whole sample, just 17 patients (18.7%) were receiving treatment for anxiety or depression with benzodiazepines and/or antidepressants. Conclusions: Anxiety and depression are disorders that are more prevalent among patients with acute coronary syndrome than in the general population, but they are generally under-diagnosed and under-treated. Patients with anxiety and depression simultaneously had higher scores on the HADS for anxiety and depression and therefore require more intensive care

Magnesium oxide prepared via metal?chitosan complexation method : application as catalyst for transesterification of soybean oil and catalyst deactivation studies.

A simple method to prepare magnesium oxide catalysts for biodiesel production by transesterification reaction of soybean oil with ethanol is proposed. The method was developed using a metal?chitosan complex. Compared to the commercial oxide, the proposed catalysts displayed higher surface area and basicity values, leading to higher yield in terms of fatty acid ethyl esters (biodiesel). The deactivation of the catalyst due to contact with CO2 and H2O present in the ambient air was verified. It was confirmed that the active catalytic site is a hydrogenocarbonate adsorption site